Return Camera Image (Stream) from ICameraView.CaptureImage()

[TheCodeTraveler]

Description of Change

API Change

This PR updates ICameraView.CaptureImage() to return the Stream captured by the camera:

// Previous (Existing) API
ValueTask CaptureImage(CancellationToken token);

to

// Updated API
Task<Stream> CaptureImage(CancellationToken token);

Developer Experience Improvement

This improves the developer experience, allowing devs to retrieve the image directly from the method, whereas the current/previous experience required them to subscribe to CameraView.MediaCaptured:

// Previous (Existing) Developer Experience
public partial class CameraPage : Content
{
  public CameraPage()
  {
      InitializeComponent();

      cameraView.MediaCaptured += HandleMediaCaptured;
      cameraView.MediaCaptureFailed += HandleMediaCaptureFailed
  }

  async void CaptureButtonTapped(object? sender, EventArgs e)
  {
      await cameraView.CaptureImage(CancellationToken.None);
  }

  void HandleMediaCaptured(object? sender, MediaCapturedEventArgs e)
  {  
      capturedImage.Source = ImageSource.FromStream(() => e.Meda);
  }
  
  async void HandleMediaCapturedFailed(object? sender, MediaCaptureFailedEventArgs e)
  {  
      await Toast.Make("Capture Failed").Show();
  }
}

// Updated Developer Experience
public partial class CameraPage : Content
{
  public CameraPage()
  {
      InitializeComponent();
  }

  async void CaptureButtonTapped(object? sender, EventArgs e)
  {
      try
      {
            var imageStream = await cameraView.CaptureImage(CancellationToken.None);
            capturedImage.Source = ImageSource.FromStream(() => imageStream);
      }
      catch(CameraException e)
      {
            await Toast.Make("Capture Failed").Show();
      }
  }
}

PR Checklist

• Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
• Has tests (if omitted, state reason in description)
• Has samples (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Changes adhere to coding standard
• Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pull/559/files

[Copilot]

Pull Request Overview

This PR refactors ICameraView.CaptureImage() to return a Task<Stream> instead of ValueTask, implements a semaphore-protected event‐based capture flow, and adds disposal logic to CameraView.

• Introduces IDisposable on CameraView for cleanup of SemaphoreSlim
• Changes CaptureImage to async Task<Stream>, uses TaskCompletionSource<Stream> with MediaCaptured/MediaCaptureFailed events
• Updates ICameraView interface signature and adjusts related bindable property defaults

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/CommunityToolkit.Maui.Camera/Views/CameraView.shared.cs	Added IDisposable, semaphore management, new CaptureImage logic
src/CommunityToolkit.Maui.Camera/Interfaces/ICameraView.shared.cs	Updated CaptureImage from ValueTask to Task<Stream>

Comments suppressed due to low confidence (2)

src/CommunityToolkit.Maui.Camera/Views/CameraView.shared.cs:221

• The new CaptureImage behavior (success, failure, cancellation, and concurrent calls) isn’t covered by existing tests—consider adding unit or integration tests to validate event unsubscription, exception paths, and semaphore behavior.

public async Task<Stream> CaptureImage(CancellationToken token)

src/CommunityToolkit.Maui.Camera/Interfaces/ICameraView.shared.cs:58

• Update any public API docs, samples, and IntelliSense comments to reflect that CaptureImage now returns a Task<Stream> instead of ValueTask and no longer relies on the MediaCaptured event.

Task<Stream> CaptureImage(CancellationToken token);